Muslim nations unlikely to overtake Christian ones in population
Recently Dr. Hans Rosling sent this message by Twitter:
“Today number of births/women does not differ between Christian vs. Muslim majority countries.”
And he provided a link to this graph showing ‘Children per woman’ vs. ‘Income per person’. In case you cannot see the graph for some reason, I have taken a screenshot:
(click image to enlarge)
In the graph, each circle represents one country in the year 2008. The size of the circle is based on the population of the country and the color is based on the largest religion. So, the largest circles, China and India, are colored red since Gapminder classifies them as ‘Eastern religions’. Sweden is colored blue because, even though a majority of the population described themselves as nonreligious, the largest religious groups is Christian.
Personally, I don’t know how Dr. Rosling determined that the number of births per woman “does not differ between Christian vs. Muslim majority countries” just by looking at this graph. I needed to download the original data from Gapminder’s website and find the averages by hand.
What I found, though, was that, according to Gapminder’s classification of countries, Muslim-majority countries do not currently seem to have the same number of children per woman (or, total fertility rate) as the other categories. Instead, as of 2010 (when the latest data is from):
- Muslim-majority countries have about 2.95 children per woman
- Christian-majority countries have about 2.45 children per woman, and
- Eastern religion-majority countries have about 2.03 children per woman.
I guess that the root of my confusion lies in Dr. Rosling’s classifications of countries. For example, China belongs to ‘Eastern religions’ even though it is officially atheist. Likewise, Puerto Rico and Liberia are unclassified, although both are strongly Christian. Israel is also unclassified, as Gapminder’s notes explain, simply to keep down the number of different categories of religions. Even though Vietnam and Thailand are considered ‘Eastern religions’, North Korea and South Korea are not classified at all.
I was trying to figure out how Dr. Rosling determined that majority-Muslim and majority-Christian countries have the same number of children per woman, so I tried re-classifying the countries myself. Dr. Rosling calls Sweden a Christian country (and I guess their flag supports that assertion), but personally I would call it ‘Secular’. A Gallup survey referenced on Wikipedia determines my list of secular countries – Any country where more than 50% of the population said they were irreligious I have considered to be Secular. By this survey even Israel is considered secular. I guess that it is OK to lump India and Bhutan together as ‘Eastern religions’, but Japan is secular, as are Germany and Canada. Among industrialized nations, the US stands out as being particularly religious, so I’ve kept it Christian.
So, I still don’t quite understand how Dr. Rosling reached his conclusion that Muslim-majority countries have the same number of children per woman as Christian-majority countries. Even by filtering many low-fertility countries like Russia and Spain out of the ‘Christian’ category and into the ‘Secular’ classification, the total fertility rate of Muslim-majority countries in 2010 was still about 2.95 while that of Christian countries (mostly Africa and the Americas south of Canada) was about 2.78. Likewise, ‘Eastern religions’ averaged about 2.47 while the secular nations were about 1.60.
Of course, TFR correlates strongly to population growth rates, since any society that produces more than 2 children per woman (like Afghanistan) will tend to grow while those that produce fewer than 2 children (which is where Italy and Spain and Russia and several other countries are today) will tend to shrink.
Gapminder also provides total fertility rate (TFR) and population values for other years besides 2010, including projections into the future, from which I have made the graph below estimating the fraction of the world’s population in each category of country:
(click image to enlarge)
One thing that surprised me was that the nations where the Gallup poll in 2006-2010 said they were Secular were, and still are, the most-populous nations, currently being about 30% of the world’s population. Due to low TFR’s, though, the Secular nations are dramatically shrinking as a percentage of the world population. Personally, I tend to think of atheism as something that is becoming more accepted while religious tendencies are on the wane, but at the nation level, the opposite seems to be the case.
Gapminder’s projections have the Christian and Muslim nations rising as percentages of the world’s population, though both Osama bin Laden and Anders Behring Breivik might be surprised to learn that Muslim-majority nations seem unlikely to surpass the Christian-majority nations any time soon.
So, perhaps Dr. Rosling just spoke a little too soon. By Gapminder’s estimates, sometime in the 2040′s the TFR of Muslim-majority nations will be less than that of the Christian-majority nations, even with the low-fertility nations like Sweden and Germany counted among the Christian countries. And, by 2100, essentially no country will be producing enough children to replace itself.